in that middle section, the mask shape is actually aligned right (not left), so the left edge begins the alpha-gradient as the stripes move left to right
You can use setMask in ActionScript to have a mask with transparency/alpha. Create the mask, and give it an instance name. Give the instance you want to mask an instance name.
Then use the following code (this is in AS3, where the mask is called "yourMask" and the instance you're masking is called "instanceToMask"):
yourMask.cacheAsBitmap = true;
instanceToMask.cacheAsBitmap = true;
instanceToMask.mask = yourMask;
the AS worked like hell
thnx so much!
what topic should i study to understand what i did?
is it going to make my file size unacceptably large?
Did you take a look at that link above? That will provides some answers. If you are using a basic vector gradient, it wont increase file size too much. Pngs may, depending on the complexity.